Methods using hydrazine in particular in the methods of preparation of cycloheptasulfimide

ABSTRACT

THE INVENTION RELATES TO A REACTANT CAPABLE OF LIBERATING ANHYDROUS HYDRAZINE IN A MEDIUM WHICH MUST BE SHELTERED FROM WATER, WHICH CONSISTS ESSENTIALLY OF AN ACTIVATED SILICA GEL CONTAINING ADSORBED HYDRAZINE HYDRATE.

United States Patent f 3,553,147 METHODS USING HYDRAZINE, IN PARTICU-LAR IN THE METHODS OF PREPARATION OF CYCLOHEPTASULFIMIDE Henri Garcia,Bagneux, France, assignor to Centre National de la RechercheScienfifique, Paris, France, a French government administration NoDrawing. Original application Dec. 27, 1965, Ser. No. 516,710, nowPatent No. 3,447,911, dated June 3, 1969. Divided and this applicationOct. 7, 1968, Ser. No. 798,502

Claims priority, applicai6ozn France, Jan. 6, 1965,

Int. Cl. C01b 21/16, 21/54 US. Cl. 252-188 Claims ABSTRACT OF THEDISCLOSURE The invention relates to a reactant capable of liberatinganhydrous hydrazine in a medium which must be sheltered from water,which consists essentially of an activated silica gel containingadsorbed hydrazine hydrate.

This application is a division of application Ser. No. 516,710 in thename of Henri Garcia, filed Dec. 27, 1965, now Pat. No. 3,447,911.

This invention relates to methods using hydrazine for producingchemicals in a reduced state, in particular cycloheptasulfimide.

Cycloheptasulfimide S NH is already known, its molecule consisting of anoctogonal heterocycle deriving from the S sulfur cycle, in which an NHgroup is substituted for an S atom.

cycloheptasulfimide exerts a powerful fungicide effect with respect toplants, yet it is only very slightly toxic for the higher organisms. Onthe other hand, known methods of preparing cycloheptasulfimide enableonly traces of this chemical to be obtained and cannot therefore beexploited on an industrial scale.

It is accordingly the primary object of this invention to providemethods which meet practical requirements to a greater degree thanheretofore, especially inasmuch as they enable cycloheptasulfimide to beprepared in large quantities under satisfactory conditions of purity andefficiency, using relatively inexpensive starting materials.

In accordance with a specific provision of the invention,cycloheptasulfimide is prepared by reacting nitrogen sulfide S N or athiotrithiazyl halide, and preferably thiotrithiazyl chloride, withhydrazine, in an enert organic solvent, sheltered from water.

The invention relates to a number of other provisions which arepreferably used jointly but which may be used singly if necessary, andmost notably to a second provision in accordance with which a hydrazinehydrate is absorbed on an activated silica gel, or on a support havingsimilar properties, whereby a reactant is formed which is capable ofliberating the hydrazine in a reaction medium while keeping thehydrating water of the initial hydrazine hydrate fixed, said hydrate isabsorbed on an activated silica gel or on a support having similarproperties.

Assuming that it is desired to prepare cycloheptasul fimide through theaction of hydrazine on nitrogen sulfide S N or on thiotrithiazylchloride S N Cl, then the procedure according to a preferred embodimentof the invention is an follows or similar thereto.

Before going into greater detail, it is thought to be necessary to citepatent application Ser. No. 299,836 filed Aug. 5, 1963, which describesmethods of preparing nitrogen sulfide S N and thiotrithiazyl chlorideClS N those two substances being the preferred starting materials forpreparing cycloheptasulfimide in accordance with the 3,553,147 PatentedJan. 5, 1971 ice method of the present invention. Hydrogen sulfide S Ncan readily be prepared by the action, in the cold condition, of excessammonia on sulfur chloride in solution in a cyclohexane, on the basis ofthe following reaction:

The ammonium chloride and the sulfur formed in the reaction precipitate,giving a solution of nitrogen sulfide in cyclohexane.

Thiotrithiazyl chloride can be formed in turn by the action under heatof excess sulfur chloride on a solution of nitrogen sulfide incyclohexane for example, by the following reaction:

In accordance with the first provision of the invention, either of thesestarting materials is caused to react in an inert organic solvent andsheltered from water, with a very powerful reducing agent and preferablywith hydrazine.

It was unforeseen that cycloheptasulfimide could be obtained with ahighly satisfactory yield (as will be apparent from the examples givenhereinafter by way of illustration) by the action of hydrazine, onnitrogen sulfide S N and thiotrithiazyl chloride, sheltered from anyhydrating water which might be present.

Tests conducted with other reducing agents such as palladium hydride,Raney nickel, sodium borohydride and hypophosphoric acid also led to theformation of more or less large traces of heptasulfimide.

Hydrazine, known to be one of the most energetic reducing agents extent,has the added advantage of leaving no reaction residues since itsdecomposition products are nitrogen and hydrogen.

When hydrazine is caused to act on nitrogen sulfide in an organicsolvent such as benzene or carbon tetrachloride, sheltered from water,the initially dark orange solution gradually discolors. Nitrogen andammonia are liberated (which can be determined by classic methods) andthere is a precipitation of sulfur. It is further possible to follow theformation of cycloheptasulfimide, which remains in solution, by infraredspectrography, by measuring the intensity of the characteristic band ofthe NH group in the wavelength region of 3340 cm.- Total discolorationof the solution indicates the end of the reaction. Determination of thevarious products formed shows that the reaction probably takes placeaccording to the following equation:

The cycloheptasulfimide formed is separated by evaporating the clearsolution obtained after filtering the reaction mixture. Well-formedcrystals are obtained which have crystallized in the rhonrbohedralsystem, and these crystals have bipyramidal or orthorhombio shapes ortake the form of slightly rhombohedral lamella. They melt at 113.5 C.and have a density of 1.992.

The same product can be obtained when thiotrithiazyl chloride is causedto react with hydrazine in the absence of hydrating water, in accordancewith the following reaction equation:

Ammonium chloride, which is insoluble in the organic solvent,precipitates with the sulfur and can therefore also be separated byfiltration.

With regard to the solvents themselves, any solvent which is inert withrespect to the reaction can be used. Benzene, cyclohexane and thesolvents provided by chlorinated hydrocarbons, such as carbontetrachloride, trichloroethylene, chloroform, and the like, are to bepreferred because of the solubility of cycloheptasulfimide in suchsolvents.

The duration of the reaction is greater when it is based onthiotrithiazyl chloride, because this substance is only slightly solublein the organic solvents considered. The duration of a reaction utilizingnitrogen sulfide will, however, be shorter since the latter is solublein these same solvents. In the latter case, therefore, more intimatecontact is ensured between the hydrazine and the nitrogen sulfide.

The method of preparing cycloheptasulfimide from thiotrithiazylchloride, though slower, has the advantage of resulting in anend-product which is purer than when starting from the nitrogen sulfide.For-assuming that the latter were prepared in accordance with the Frenchpatent application hereinbefore referred to, it would not be entirelyfree from impurities; yet these impurities are eliminated during thesubsequent reaction of the nitrogen sulfide with sulfur chloride to formthiotrithiazyl chloride.

In these methods, the higher the temperature, the greater the reactionspeed. On the other hand, the temperature cannot be raised to a greatextent owing to the relatively low boiling points of some of the organicsolvents and, above all, because of the fragility of the hydrazine andthe cycloheptasulfimide formed, so that results become uncertain whenthe operating temperature exceeds 50 C. The preferred temperature rangeis between 45 C. and 50 C. approximately.

With more particular reference to hydrazine, it is well known that, forall practical purposes, the latter is commercially available only in theform of the monohydrate N H H O, which contains only 54.5% of hydrazine.This monohydrate is unusable in its existing form owing to thesensitivity of the reaction products to alkaline hydrolysis.

This drawback can be advantageously overcome by proceeding in accordancewith the second provision of the invention, by causing the hydrazinehydrate to be absorbed on a porous support such as an activated silicagel which is subsequently capable of liberating the hydrazine in themidst of the reaction mixture in which the hydrazine must operate, thehydrating water of the initial hydrazine hydrate being retained in saidporous support. The silica gel utilized for this operation shouldpreferably be of granular form.

The hydrazine-retaining granules obtained thus are introduced into thesolvent containing the nitrogen sulfide S N in solution or thethiotrithiazyl chloride in suspension. It will be noted that thehydrazine introduced into the reaction medium referred to fully retainsits reducing capacity, since it is possible to observe theaforementioned liberations of nitrogen and ammonia and the formation ofcycloheptasulfimide, which may be monitored by infrared spectography asstated precedingly.

Said silica gel granules may retain 16-17% or more of hydrazine in theirstructure. The use of silica gel granules containing largerconcentrations of hydrazine will be found less advantageous, as thegranules then tend to become sticky and consequently difficult to use.

Conversely, granules with hydrazine contents of less than 16-17% assumethe form of dry granules that can be preserved indefinitely. Theadvantages of this method of utilizing hydrazine will readily beappreciated. Hydrazine-charged granules obtained in accordance with thepresent invention could therefore be used for reducing, in an organicsolvent, compounds other than nitrogen sulfide S N or thiotrithiazylchloride. The invention permits in particular of utilizing hydrazine,even if it has been initially hydrated, for reducing, in an inertorganic solvent, any water sensitive compound that is readilyhydrolyzable or capable of furnishing readily hydrolyzable reductioncompounds.

By way of non-limitative example, it is possible to obtain silica gelgranules containing from 10 to 13.5% of hydrazine by proceeding asfollows:

The first step is to prepare, in the manner well known per se, a silicagel which is activated by neutralizing a sodium silicate withhydrochloric acid having a concentration of 23 Baum. Theend-of-neutralization indicator could be methyl orange, for instance.The gelatinous silica precipitate formed is allowed to rest for aboutten hours, then washed several times with distilled water, after whichit is dried at C. and finally roasted at 300 C. The still-hot roastedgel is then dipped and washed several times in hot distilled water toeliminate the sodium salts coexisting with the silica gel, and this iscontinued until the washing water gives no further precipitate whensilver nitrate is added. The gel obtained thus is finally dried at 400C.

This gel is granulated and placed in a rotating cylindrical containerwhich is cooled energetically by means of a stream of cold water.Hydrazine monohydrate is then added to this gel slowly until aproportion of 25 cubic centimeters of hydrazine monohydrate per 75 gramsof activated silica gel is obtained. Since this absorption processcauses considerable heat to be given oil, the cylindrical container mustbe cooled very energetically. Dry grains containing the reducing agentare thus ultimately obtained and can be preserved in carefully sealedflasks possibly made of coloured glass, and these granules can be storedindefinitely as they are if they are sheltered from dampness.

By way of indication, the concentration of basic hydrazine N H in theactivated silica gel granules can be determined by a colorimetric methodconsisting in placing the granules in contact with a solution ofp-dimethylaminobenzaldehyde in a slightly acid medium. This causes abright orange diazo dye to form, the optical density of which is thenmeasured with a photometer and compared with a calibration curve plottedpreviously by means of solutions prepared from pure crystallizedhydrazine dichlorohydrate.

Whilst the invention will have been rendered sufficiently clear from theforegoing, it is proposed to give hereinbelow two examples of thepreparation of cycloheptasulfimide involving the precedingly describedprovisions of the invention.

EXAMPLE 1 Three grams of crystallized nitrogen sulfide S N are dissolvedin 300 ml. of a benzene solution contained in a 500 ml. Erlenmeyerequipped with a reflux condenser. The formation of a dark orange coloredsolution may be observed. Ten grams of activated silica granulescontaining 12% of base hydrazine and prepared as hereinbefore describedare added to this solution. The reaction starts immediately and isrevealed by an abundant liberation of gas and a heating up of thesolution. Care is exercised to keep the reaction medium at a temperatureof about 46 C. for eight to ten hours. The reaction is complete when thesolution becomes absolutely colorless. The stages in this reaction canalso be followed by measuring the intensity of absorption in thewavelength band in the region of 3340 cmf characteristic of the NHradical. The mixture is then filtered and the clear solution purified bypassing it over a thin layer of neutral activated alumina, the solutionbeing finally evaporated to give crystals which, in solution reveal theinfrared spectrum characteristic of cycloheptasulfimide and whichpossess the physical properties referred to previously. The quantity ofpure substance obtained is 1.845 grams, corresponding to a yield of 96%with respect to the weight of the starting nitrogen sulfide.

EXAMPLE 2 Eight grams of thiotrithiazyl chloride are placed in solutionin 300 ml. of carbon tetrachloride, in the same apparatus as before, and30.5 grams of activated silica granules retaining 10.28% of basehydrazine in absorbed form are added to the reaction medium. Thetemperature is maintained at about 46 C. The start of the reaction isrevealed by an abundant liberation of nitrogen and ammonia and by thedark red coloring of the solvent, due probably to the initialdecomposition of the thiotrithiazyl chloride into nitrogen sulfide. Hereagain, the end of the reaction is indicated when the solution becomesabsolutely colorless, the reaction lasting five to six days. Thecycloheptasulfimide crystals are obtained from the clear solution by thesame method as that of Example 1, the yield being 3.150 grams of purecycloheptasulfirnide, corresponding to an efliciency of 67.6%.

In both these experiments the product obtained takes the form of whitecrystals shaped as rhombohedral prisms. They melt at 113.5 C. anddecompose in the process, and their density is 1.992. A gravimetricanalysis of this product also bears out the formula S NH:

Predicted percentage: N, 5.85; S, 93.72; H, 0.43. Actual percentage: N,5.92; S, 92.92; H, 0.56.

The infrared spectrum of the pure product or solution in carbondisulfide in a tank 0.3 mm. thick gives two typical, very intense bandsat 3335 cmr and 807 cm.- which correspond to the NH" group and the SNbond, respectively.

It goes without saying that the invention is by no means limited to thespecific applications or forms of embodiment thereof more particularlydescribed hereinabove, but that many changes and substitutions may bemade without departing from its scope as defined in the claims.

What I claim is:

1. A process for producing, starting from a hydrazine hydrate, a solidand dry reactant capable of liberating hydrazine in a reaction mediumwhile sheltering the same from the hydrating water of the initialhydrazine hydrate, which comprises adsorbing said hydrazine hydrate onactivated silica gel in amounts such that the 6 final content inhydrazine of said activated silica gel be less than about 17%.

2. A process according to claim 1 wherein the hydrazine hydrate ishydrazine monohydrate and the activated silica gel is granulated silicagel.

3. A process according to claim 1 wherein said hydrazine is adsorbed onactivated silica gel in amounts such that the final content in hydrazineof said activated silica gel ranges between about 10 and about 13.5%.

4. A solid and dry reactant capable of liberating hydrazine in areaction medium in an anhydrous form which consists essentially ofactivated silica gel containing hydrazine hydrate adsorbed in its massin amounts such that the content in hydrazine of said activated silicagel is less than about 17%.

5. A solid and dry reactant according to claim 4, wherein the content inhydrazine of said activated silica gel ranges from about 10 to about13.5%.

References Cited UNITED STATES PATENTS 2,963,407 12/1960 Lewis 23l90XFOREIGN PATENTS 524,865 5/1956 Canada 23190 OTHER REFERENCES Rose etal.; The Condensed Chemical Dictionary, 6th edition, Reinhold Publ. Co.,New York, 1961, pages 1017 and 1018.

LEON D. ROSDOL, Primary Examiner I. GLUCK, Assistant Examiner US. Cl.X.R. 23190, 356

